The proverb goes, "In the world, just a step ahead is darkness." It's a lesson to be prepared for the uncertainties of life. Even in unexpected situations, maintaining composure and dealing with them calmly will surely lead to a way out. From childhood, I've been taught this.
...Even if, somehow, the inside of the closet connects to a cave.
Calmly closing the door, taking a deep breath, and counting to twenty. Afterward, I opened the door again to ensure nothing had changed.
-----
For now, let's give up on using the closet. At a glance, there didn't seem to be any dangerous animals inside. Tying the door shut with wire, postpone investigating the cause. It's okay; I'm calm. Let's have breakfast. If I'm hungry, my mind won't work properly.
Finishing breakfast without a clear idea. Beyond the closet, something like a cave extends beyond where there should be a wall. In other words, the inside of the closet isn't a normal space. Or maybe it's me who isn't normal? Let's stop. For now, let's assume my mind is normal. If we don't assume that, the story won't progress.
Report to the police? No, this abnormal space could end anytime. If I make a fuss, call the police, and everything returns to normal, my life would be over. Even a recluse should have a peaceful life in their own way.
Consult with someone other than the police? No good. Not to brag, but I don't have anyone I can open up to. I haven't contacted my parents for over five years—not because we had a falling out, it's just troublesome. I can't imagine my parents being happy about such troublesome matters.
Leaving things as they are is also not an option. Besides not being able to use the closet, leaving unknown and potentially dangerous areas unattended won't lead to a peaceful life. Yeah, it's definitely not an option.
--
I'll have to investigate on my own.
Sounds interesting.